Many people know that
condensing boilers are more efficient than the generation of boilers that went
before; but less people know that installing a condensing boiler may do little
to reduce gas consumption if you don’t also use the right controls.*

A condensing boilers
effectively recycles heat that would otherwise escape to the ouitside air
through its flue. It achieves this by causing the gases given off by the
burning process to condense, and form liquid in the boilers heat exchanger and
in its flue. So the heat from the waste gases is transferred to the heat
exchanger via the liquid condensate

The problem is that the
gases will only condense up to 57C (for the technically minded this is known as
the dew point of a gas). So there is a big advantage in making a condensing
boiler operate at a relatively low temperature

To achieve
this it is
important to use the correct controls

For the last ten years a
form of central heating control has been available in Europe, and is used
widely, in Germany and Holland in particular. It’s called Weather Compensation,
and is an outside sensor which measures the outside temperature. By knowing
what the outside temperature is, the boiler can predict how much heat to send
to the radiators to achieve a steady even temperature inside the house. The
user can alter the temperature inside by a dial in a very similar way to the
dial of a conventional thermostat.

Temperatures in London are
fairly moderate, so the boiler rarely has to raise its temperature beyond the
level at which it condenses. Only on very cold winter days and nights will the
boiler raise it temperature to its maximum. According to Viessmann, the German
company making some of the best quality boilers available, the use of Weather
Compensation can reduce energy consumption by 15% compared with a conventional
room thermostat.

Weather Compensation is the
form of heat control my company recommends the most. But even if you don’t have
that, a modulating room thermostat will prevent your boiler from racing up to
its highest temperature, and will help it to stay condensing for longer
periods. Conventional room thermostats do not work in the same way.

My company can also provide
controls that keep the boiler condensing for longer as it heats a hot water
cylinder. Again, a conventional cylinder thermostat will not work in the same
way.

All
of these heating controls are widely available from firms like Vaillant and
Viessmann and
Atag